Dicing-free LED fabrication

Abstract

Provided is a method of fabricating a light-emitting diode (LED) device. The method includes providing a substrate having opposite first and second sides. A semiconductor layer is formed on the first side of the substrate. The method includes forming a photoresist layer over the semiconductor layer. The method includes patterning the photoresist layer into a plurality of photoresist components. The photoresist components are separated by openings. The method includes filling the openings with a plurality of thermally conductive components. The method includes separating the semiconductor layer into a plurality of dies using a radiation process that is performed to the substrate from the second side. Each of the first regions of the substrate is aligned with one of the conductive components.

What is claimed is: 
     
       1. A method, comprising:
 providing a substrate having opposite first and second sides, wherein the first side has a semiconductor layer formed thereon; 
 forming a photoresist layer over the semiconductor layer such that an entire portion of a bottom surface of the photoresist layer is formed on a top surface of the semiconductor layer; 
 patterning the photoresist layer into a plurality of photoresist components, the photoresist components being separated by openings; 
 filling the openings with a plurality of conductive components; and 
 separating the semiconductor layer into a plurality of dies using a radiation process that includes selectively radiating a plurality of first regions of the substrate from the second side, each of the first regions of the substrate being aligned with a respective one of the conductive components. 
 
     
     
       2. The method of  claim 1 , wherein the photoresist layer is formed in a street line region of the semiconductor layer. 
     
     
       3. The method of  claim 1 ,
 wherein the radiation process is carried out in a manner so that a plurality of second regions of the substrate are unradiated, each of the second regions being aligned with one of the photoresist components; and 
 wherein as a result of the radiating, the first regions of the substrate become de-coupled from the semiconductor layer, and the second regions of the substrate remain coupled to the semiconductor layer. 
 
     
     
       4. The method of  claim 3 , wherein the radiating causes a nitrogen gas to be released at interfaces between the first regions of the substrate and the semiconductor layer; and further including: removing the substrate along with portions of the semiconductor layer that are aligned with and coupled to the second regions of the substrate. 
     
     
       5. The method of  claim 3 , further including, before the radiating:
 forming a glue material over the conductive components and the photoresist components; 
 forming a light-to-heat conversion layer on a glass substrate; and 
 bonding the glass substrate to the glue material in a manner so that the light-to-heat conversion layer is disposed in between the glass substrate and the glue material. 
 
     
     
       6. The method of  claim 5 , further including, after the radiating:
 performing a laser scan through the glass substrate to cause heating in the light-to-heat conversion layer, thereby separating the glass substrate from the light-to-heat conversion layer; 
 de-bonding the glass substrate; and 
 thereafter removing the glue material, the removing the glue material also removing the photoresist components. 
 
     
     
       7. The method of  claim 1 , wherein:
 the substrate includes a sapphire material; 
 the conductive component is thermally conductive; and 
 the semiconductor layer includes a p-type gallium nitride layer, an n-type gallium nitride layer, and a multiple quantum well that is disposed in between the p-type gallium nitride layer and the n-type gallium nitride layer. 
 
     
     
       8. The method of  claim 1 , further including, before the forming the photoresist layer, forming one of: an ohmic layer, a reflective layer, and a capped layer over the semiconductor layer; and wherein the forming the photoresist layer is carried out in a manner so that the semiconductor layer and the photoresist layer are disposed on opposite sides of the ohmic layer. 
     
     
       9. A method, comprising:
 forming a patternable layer over a semiconductor layer, the semiconductor layer being disposed over a substrate; 
 patterning the patternable layer to form a plurality of patternable features, the patternable features being spaced apart from one another; 
 forming a plurality of conductive features between the patternable features; 
 forming a glue material over the conductive features; 
 forming a light-to-heat conversion layer on a glass substrate; and 
 bonding the glue material to the light-to-heat conversion layer and the glass substrate; and 
 dividing the semiconductor layer into a plurality of different portions, wherein the dividing is performed at least in part by selectively radiating a plurality of regions of the substrate that are each aligned with a respective one of the conductive features. 
 
     
     
       10. The method of  claim 9 , wherein the semiconductor layer is formed on a first side of the substrate, and wherein the radiating is performed from a second side of the substrate opposite the first side. 
     
     
       11. The method of  claim 9 , wherein the patternable layer includes a photoresist material and is formed over a scribe line region of the substrate. 
     
     
       12. The method of  claim 9 , wherein the dividing is performed such that regions of the substrate aligned with the patternable features are not radiated. 
     
     
       13. The method of  claim 9 , wherein the plurality of regions of the substrate decouples from the semiconductor layer after being radiated. 
     
     
       14. The method of  claim 9 , wherein the semiconductor layer includes:
 a p-type gallium nitride layer; 
 an n-type gallium nitride layer; and 
 a multiple quantum well located between the p-type gallium nitride layer and the n-type gallium nitride layer. 
 
     
     
       15. A method, comprising:
 forming a patterned mask over a semiconductor layer that is disposed on a substrate, wherein the patterned mask is formed to have a bottom surface, and wherein an entire portion of the bottom surface of the patterned mask is formed over a topmost surface of the semiconductor layer, the patterned mask containing a plurality of openings; 
 forming a plurality of conductive devices in the openings; and 
 transforming the semiconductor layer into a plurality of dies at least in part by applying radiation to a plurality of first regions of the substrate that are each aligned with a respective one of the conductive devices while leaving a plurality of second regions of the substrate unradiated, wherein the radiation is applied so that a nitrogen gas is released at interfaces between the first regions of the substrate and the semiconductor layer. 
 
     
     
       16. The method of  claim 15 , wherein the patterned mask includes a patterned photoresist layer, and wherein the patterned mask is formed over a street line region of the semiconductor layer. 
     
     
       17. The method of  claim 15 , further comprising: removing the substrate along with unradiated portions of the semiconductor layer. 
     
     
       18. The method of  claim 15 , further comprising:
 forming a glue material over the conductive devices and the patternable mask; 
 attaching the glue material to a glass substrate having a light-to-heat conversion layer disposed thereon, wherein the light-to-heat conversion layer is disposed in between the glass substrate and the glue material; 
 performing a laser scan through the glass substrate to generate heat in the light-to-heat conversion layer, thereby separating the glass substrate from the light-to-heat conversion layer; 
 detaching the glass substrate; and 
 removing the glue material along with the patternable mask. 
 
     
     
       19. The method of  claim 15 , wherein:
 the substrate includes a sapphire material; 
 the conductive devices include metal; and 
 the semiconductor layer includes a p-type gallium nitride layer, an n-type gallium nitride layer, and a multiple quantum well that is disposed in between the p-type gallium nitride layer and the n-type gallium nitride layer. 
 
     
     
       20. The method of  claim 15 , wherein the radiation includes a 248 nanometer KrF laser.